According to a conventional lubricating structure for a spline-fitted portion, it is common to form an axially extending hole inside a spline shaft having outer spline teeth formed on an outer circumferential surface thereof, introduce a lubricating oil into the hole from an end opposite to an end having the outer spline teeth, and supply the lubricating oil to the spline-fitted portion. There has also been proposed a structure of scraping up a lubricating oil by the rotation of a rotation shaft to cause droplets of the lubricating oil to adhere to a surface of a member, flowing down the droplets of the lubricating oil along the surface of the member and supplying the droplets of the lubricating oil to a spline-fitted portion (refer to, for example, Japanese Patent Laying-Open No. 2014-231339 (PTD 1)).